The physical plant at the main campus of a large state university recieves daily requests to replace fluorescent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 45 and a standard deviation of 3. Using the empirical rule, what is the approximate percentage of lightbulb replacement requests numbering between 42 and 45?

Do not enter the percent symbol.
ans = %

Answer:

90

Step-by-step explanation:

5x – 2y + (7x – y)

Combine like terms

12x -3y

Let x = 7 and y = -2

12(7) -3(-2)

84 +6

90

Answer:

90

Step-by-step explanation:

Hi there!

We are given this expression:

5x-2y+(7x-y) and we want to evaluate it if x=7 and y=-2

First, let's combine like terms, as that will make it easier for when we substitute the values into the expression

Open up the parentheses

5x-2y+7x-y

Combine like terms

12x-3y

Now substitute 7 as x and -2 as y into the expression

12(7)-3(-2)

Multiply

84+6

Add

90

Hope this helps!

Answer:

27 by 27

Step-by-step explanation:

Let the sides be x and y. The problem is essentially asking:

Given 2(x+y)=108, maximize xy.

We know that x+y=54. By the Arithmetic Mean - Geometric Mean inequality, we can see that [tex]\frac{x+y}{2} \ge \sqrt{xy[/tex]. Substituting in x+y=54, we get [tex]27\ge\sqrt{xy}[/tex], meaning that [tex]729 \ge xy[/tex]. Equality will only be obtained when x=y (in this case it will generate the maximum for xy), so setting x = y, we can see that x = y = 27. Hence, 27 is the answer you are looking for.

Answer: Because [tex]\frac{\pi }{3} =\frac{180\°}{3} =60\°[/tex], therefore [tex]\frac{\pi }{3} =60\°[/tex].

Answer:

2[tex]\sqrt{2}[/tex]

Step-by-step explanation:

See the photo for the steps. :)

260 pairs

Step-by-step explanation:

220-100= 120

(29200+2000)÷120= 260

JWL = JWI + IWL

87 = (2x + 24) + (3x - 12)

87 = 5x + 12

5x = 75

x = 15

Hope this helps!

The value of the variable x will be 15. Then the correct option is A.

The angle is the distance between the intersecting lines or surfaces. The angle is also expressed in degrees. The angle is 360 degrees for one complete spin.

Linear angle - If the total of two angles is 180 degrees, they are said to be linear angles.

The measure of the angle ∠JWL will be 87°.

The angle ∠JWI and angle ∠IWL will be the linear angle.

Then the sum of the angle ∠JWI and angle ∠IWL is equal to the angle ∠JWI.

          ∠JWI + ∠IWL = 87°

(2x + 24) + (3x – 12) = 87

                    5x + 12 = 87

                           5x = 87 – 12

                           5x = 75

                             x = 75 / 5

                             x = 15

Thus, the value of the variable x will be 15.

Then the correct option is A.

More about the angled link is given below.

https://brainly.com/question/15767203

#SPJ5

Answer: This quadratic equation has two real solutions.

Step-by-step explanation:

[tex]y=x^{2} -11x+7\\\\D=(-11)^{2} -4 \cdot 7=121-28=93 \: > 0\\\\x=\dfrac{11 \pm \sqrt{93} }{2}[/tex]

Answer:

A) -3/2

Step-by-step explanation:

You pick the difference between the two points and divide them.

y-axis: 2-(-1)= 3

x-axis: -3-(-1) = -2

So slope is -3/2

Answer:

[tex] \frac{x}{5} [/tex]

Step-by-step explanation:

[tex]f {}^{ - 1} (x)[/tex]

means inverse.

Find the inverse of the function.

[tex]f(x) = 5x[/tex]

Replace y with and vice versa.

[tex]x = {5y}[/tex]

Solve for y

[tex] \frac{x}{5} = y[/tex]

The inverse function is

[tex] \frac{x}{5} [/tex]

Answer:

y=-\frac{2}{3}\approx -0.666666667

Answer:

50/60 = .8333=  83.33%

Step-by-step explanation:

The probability that the call arrived when the switchboard was not fully busy is 0.75.

A probability distribution that is symmetric about the mean is the normal distribution, sometimes referred to as the Gaussian distribution. It demonstrates that data that are close to the mean occur more frequently than data that are far from the mean. The normal distribution appears as a "bell curve" on a graph.

Given:

Here X follows uniform distribution with parameter a and b.

Where,

a = 0 and b = 1.

Then,

The density function of Y is given by:

P( 15 < Y ≤ 60)

or, P( 0.25 < Y ≤ 1)

So,  P( 0.25 < Y ≤ 1) = [tex]\int\limits^{1}_{0.25}{f(y) \, dy[/tex]

                                = [tex][y]^1 _ {0.25}[/tex]

                                = (1- 0.25)

                                = 0.75

Hence, The probability that the call arrived when the switchboard was not fully busy is 0.75.

Learn more about Normal Distribution here:

https://brainly.com/question/29509087

#SPJ2

Answer:

(x - 3/8)^2 = x^2 - 3/4x + 9/64

Step-by-step explanation:

Step-by-step explanation:

divide the number with x by 2 and get the square of that number and add that number to this given equation

number with x = -3/4

= x^2 - 3/4 x + 9/64

= (x -3/8) ^2

Answer:

The last one

Step-by-step explanation:

What we know:

We have a total of 16 coins

The 16 coins consist of dimes and quarters

The value of the coins is 3.10

The value of a dime is .10

The value of a quarter is .25

Using this information we can create a system of linear equations

First off we know that we have a total of 16 coins which consist of dimes and quarters

The number of Quarters can be represented by q and then number of dimes can be represented by d.

If we have a total of 16 coins then q + d must equal 16

So equation 1 is q + d = 16

Now we need to create a second equation

We know that the total value of the coins is 3.10 and we know that the coins consist of dimes and quarters

As you may know a quarter has a value of .25 cents and a dime has a value of 10 cents

If the total value of the coins is 3.10 the the number of dimes (d) times .10 + the number of Quarters times .25 must equal 3.10

This can also be written as

.25q + .10d = 3.10

So the two equations are

q + d = 16 and .25q + .10d = 3.10

These equations are shown in the last answer choice

Note: b is very similar to d

However the the value of the coins are incorrect in B

In B the value of the dime is represented by 10 which is not correct because the value of a dime is .10 not 10

I'll be referring to each of these numbers as x and y.

x + y = 4

(x^2) + (y^2) - 3(x)(y) = 76

x = 4 - y

(4 - y)^2 + (y^2) - 3(4 - y)(y) = 76

(4 - y)(4 - y) + y^2 - (3y)(4 - y) = 76

16 - 4y - 4y + y^2 + y^2 - 12y + 3y^2 = 76

16 - 20y + 5y^2 = 76

5y^2 - 20y - 60 = 0

y^2 - 4y - 12y = 0

(y - 6)(y + 2) = 0

y = 6 or -2

x = 4 - 6 = -2

x = 4 - - 2 = 6

As you can see, we got the same numbers for both x and y, -2 and 6. Therefore, the two numbers are -2 and 6. But, we can check our work to ensure that the answer is correct.

x = -2

y = 6

6 - 2 = 4

4 = 4

(-2)^2 + (6^2) - 3(-2)(6) = 76

4 + 36 - 3(-12) = 76

40 + 36 = 76

76 = 76

Hope this helps!

Answer:

X and y = -2 or 6

Step-by-step explanation:

Answer:

The correct answer is "Test 20%, Service 10%".

Step-by-step explanation:

As we know,

The coefficient of variation (CV) is:

⇒ [tex]CV=\frac{Standard \ deviation}{Mean}\times 100[/tex]

Now,

CV of test will be:

= [tex]\frac{40}{200}\times 100[/tex]

= [tex]20[/tex] (%)

CV of service will be:

= [tex]\frac{2}{20}\times 100[/tex]

= [tex]10[/tex] (%)

Answer:

1 hour and 40 minutes

Step-by-step explanation:

→ Convert 3 hr and 25 minutes to minutes

( 3 × 60 ) + 25 = 205 minutes

→ Convert 1 hr and 45 minutes to minutes

( 1 × 60 ) + 45 = 105 minutes

→ Minus the answers from each other

205 - 105 = 100 minutes

→ Convert 100 minutes to hours and minutes

1 hour and 40 minutes

Answer:

the 3rd, 4th, and 5th one

Step-by-step explanation:

Answer:

Step-by-step explanation:

:)

Answer:

2nd option,

The function is negative for all read values of x where -6<x<-2

The function f(x) = (x + 2)(x + 6) is a quadratic function, and the function is negative for all real values of x where –6 < x < –2.

Quadratic functions are functions that have an exponent or degree of 2

The function is given as:

f(x) = (x + 2)(x + 6)

From the graph of the function, the vertex is at (-4,-4) and the x-intercepts are at x = -6 and x = -2

Since the vertex is minimum, then the function is negative for all real values of x where –6 < x < –2.

Read more about x-intercepts at:

https://brainly.com/question/3951754

Answer:

[tex](f-g)(4) = -59[/tex]

Step-by-step explanation:

We are given the two functions:

[tex]f(x)=4x-3\text{ and } g(x) = x^3 +2x[/tex]

And we want to find the value of:

[tex](f-g)(4)[/tex]

Recall that this is equivalent to:

[tex](f-g)(4) = f(4) - g(4)[/tex]

Find f(4):

[tex]f(4) = 4(4)-3 = 13[/tex]

And find g(4):

[tex]g(4) = (4)^3 + 2(4) =72[/tex]

Substitute:

[tex](f-g)(4) = (13)-(72)[/tex]

And subtract. Hence:

[tex](f-g)(4) = -59[/tex]

Step-by-step explanation:

I love this question!

So there are a couple different ways of solving this. You feel free to ignore whichever one makes less sense.

Subtracting First

The first option is taking f(x) and g(x) and subtracting them, then introducing the number.

The calculation:

f(x) - g(x)

Substitute.

4x - 3 - (x^3 + 2x)

Multiply out the negative.

4x - 3 - x^3 - 2x

Rewrite.

-x^3 + 4x - 2x - 3

Simplify.

-x^3 + 2x - 3

Then, replace x with 4.

-(4)^3 + 2(4) - 3

Simplify.

-64 + 8 - 3

Add.

-59

Making x = 4 first

Here, we'll do what's on the tin. Find f(4) and g(4), then subtract them.

f(x) = 4x - 3

f(4) = 4(4) - 3

f(4) = 16 - 3

f(4) = 13

Then find g(4):

g(x) = x^3 + 2x

g(4) = (4)^3 + 2(4)

g(4) = 64 + 8

g(4) = 72

Then, subtract these two:

f(4) - g(4) = 13 - 72

f(4) - g(4) = -59

Answer:

Either way, the answer is -59

lim ( sinx-1)/(x-1)

x=>0

apply x=0

(sin(0)-1)/(0-1)

(0-1)/(-1)

=1

Answer:

False

Step-by-step explanation:

You first need to distribute the -4 to (x+4).

Answer:

1/120

Step-by-step explanation:

For the first letter, you have a 1/5 chance of getting w

On the second you have a 1/4 chance to get the r

Then 1/3 and 1/2

Next you just multiply the bottom numbers

That gives you how many diffrent outcomes there can be. Put that over 1 and you have your answer.

Hope this helps <3

Answer:

The height is 20 meters

Step-by-step explanation:

First set up the equation (Area)80=bh/2 then set up another equation, (height) h=4+2b (base). After this you can substitute h in the equation to end up with 80=(b(2b+4))/2 simplify it to get 80=b^2+2b then solve. The base is 8 meters, plug into the formula that we made before and you find the height is 20 meters.

9514 1404 393

Answer:

  B. neither perpendicular nor parallel

Step-by-step explanation:

If the lines were perpendicular, the coefficients would be swapped and one negated. (You would have 8x -y = c, or 9x +2y = c in the system.)

If the lines were parallel, the coefficients in the two equations would only differ by a common factor. (Both equations would reduce to 2x -9y = c, or x +8y = c.)

The lines are not the same line (coefficients are different).

So, the only reasonable description is ...

  neither perpendicular nor parallel

Answer:

The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.

Step-by-step explanation:

Before testing the hypothesis, we need to understand the central limit theorem and subtraction of normal variables.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Apartment:

38 out of 78, so:

[tex]p_A = \frac{38}{78} = 0.4872[/tex]

[tex]s_A = \sqrt{\frac{0.4872*0.5128}{78}} = 0.0566[/tex]

Home:

46 out of 84, so:

[tex]p_H = \frac{46}{84} = 0.5476[/tex]

[tex]s_H = \sqrt{\frac{0.5476*0.4524}{84}} = 0.0543[/tex]

Test if the there a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees:

At the null hypothesis, we test if there is no difference, that is, the subtraction of the proportions is equal to 0, so:

[tex]H_0: p_A - p_H = 0[/tex]

At the alternative hypothesis, we test if there is a difference, that is, the subtraction of the proportions is different of 0, so:

[tex]H_1: p_A - p_H \neq 0[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{s}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, and s is the standard error.

0 is tested at the null hypothesis:

This means that [tex]\mu = 0[/tex]

From the samples:

[tex]X = p_A - p_H = 0.4872 - 0.5476 = -0.0604[/tex]

[tex]s = \sqrt{s_A^2 + s_H^2} = \sqrt{0.0566^2 + 0.0543^2} = 0.0784[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{s}[/tex]

[tex]z = \frac{-0.0604 - 0}{0.0784}[/tex]

[tex]z = -0.77[/tex]

P-value of the test and decision:

The p-value of the test is the probability of the difference being of at least 0.0604, to either side, plus or minus, which is P(|z| > 0.77), given by 2 multiplied by the p-value of z = -0.77.

Looking at the z-table, z = -0.77 has a p-value of 0.2207.

2*0.2207 = 0.4414

The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.

Explanation:

Stratified sampling involves breaking a population of people into separate groups, where there isn't any overlap.

An example would be having a high school with freshmen, sophomores, juniors and seniors. A person can only belong to one group (so we can't have someone whos a freshman and a sophomore at the same time for instance). In that example, each group or strata is a different grade level.

As for this particular problem, each strata is a different ethnicity, and there are 6 strata total.

The researcher is using stratified sampling. The correct option is C.

A method of sampling from a population that can be divided into subpopulations is known as stratified sampling in statistics. When subpopulations within a larger population differ, it may be desirable to sample each subpopulation separately in statistical surveys.

Stratified sampling involves breaking a population of people into separate groups, where there isn't any overlap.

An example would be having a high school with freshmen, sophomores, juniors, and seniors. A person can only belong to one group (so we can't have someone whos a freshman and a sophomore at the same time for instance). In that example, each group or strata is a different grade level.

As for this particular problem, each stratum is different ethnicity, and there is 6 strata total.

To know more about stratified sampling follow

https://brainly.com/question/1954758

#SPJ5

Answer:

The standard error of a proportion p in a sample of size n is given by: [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

In this question:

The standard error of a proportion p in a sample of size n is given by: [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]